As visible in this screenshot. I suspect it's due to floating point rounding, but I also couldn't manage any correction for that. <img width="640" alt="screen shot 2016-12-21 at 5 44 06 pm" src="https://cloud.githubusercontent.com/assets/7651280/21381143/5b0c5930-c7a5-11e6-9695-ce7d0ba2b267.png">